Owing to the advantages of high efficiency, reduced energy consumption, etc., the liquid-solid cyclone separation technology is widely used in oil refining and chemical production. Along with the development of the heavy oil refining technology, recovery and treatment of waste porous catalysts containing oil becomes a challenge restricting the development of oil refining technologies. The cyclone-scrubbing-desorption technology solves effectively the problem of deoiling porous particles containing oil. It has been found in the research on the cyclone-scrubbing-desorption technology that microparticles not only revolve around the cyclone field center (liquid-solid cyclone separation in traditional sense), but also rotate around instantaneous axes of their own. The rotation motion of the particles reinforces separation of oil entrapped in the particles. In order to study the effect of microparticle rotation motion in reinforcing separation of pollutants in a cyclone field, there is proposed a method of determining microparticle rotation motion in a cyclone field, and there is developed a test device.
Many efforts have been devoted to the study of rotation motion of particles suspended in a liquid shear flow field. However, due to the complexity of the flow field and the restriction of the test techniques, the study is basically limited to simple shear flow under a condition of small particle Reynolds numbers. Little study has been done on particle rotation motion in turbulence with high particle Reynolds numbers.
Simon Klein, et al. (Measurement Science and Technology, 2013, Vol. 24, No. 2, pp. 1-10) reported a test technique that measures simultaneously in three dimensions the trajectories, the translation, and the rotation of finite-size inertial particles together with the turbulence flow, wherein three high-speed CMOS cameras were used to measure the three dimensional trajectories of the particles by an LPT method, and the rotation motion of the particles in a von Kármán flow field was analyzed by tracking the temporal evolution of a plurality of 100 μm fluorescent particles embedded in the surface of the spherical particles of a super water absorbent polymer. Due to the super water absorbing capacity, the polymer particles grew from 1-2 mm to about 10 mm in diameter after immersed in water, and the density of the particles was comparable with water. The frame frequency of the three high-speed CMOS cameras was 2900 fps, and the image resolution was 768×768.
Colin R. Meyer, et al (Rotational diffusion of particles in turbulence, arXiv preprint arXiv:1301.0150, 2013) determined the rotation motion of spherical and elliptical particles in a symmetrically stirred tank using stereoscopic particle image velocimetry (SPIV). The diameter of the spherical particles was 8 mm, and the major and minor axes of the elliptical particles were 16 mm and 8 mm. The density of the particles was 1007 kg/m3. The particle Reynolds numbers of the spherical and elliptical particles in the flow field were 22 and 63, respectively. The time resolution (frame frequency of the camera) in the measurement was 14.773 Hz. The measured rotation velocity was [Ωx,Ωy,Ωz]=[−0.012,−0.029,0.021] Rad/s for the spherical particles, and [Ωx,Ωy,Ωz]=[−0.024,−0.052,0.011] Rad/s for the elliptical particles.
However, for a liquid-solid micro-cyclone, the maximum tangent velocity in the cyclone field was up to 8-10 m/s, and the diameter of the particles to be separated was generally on the micron scale. This may require higher time and space resolution in measurement.
In view of the above problems, starting from increasing the identifiability of rotating particles, a need exists for methods and a devices for determining synchronously the revolution and rotation of a microparticle in a cyclone field using stereoscopic high-speed digital photographing technique.